Most trainers define low-impact as any exercise where one foot stays on the ground at all times. But rather than doing single-leg dead lifts until keeling over, we rounded up 21 low- (or no!) impact exercises worth trying:

1. Walking

Walking is a stress-free way to get moving. If taking a lesiurely stroll is too easy, there are plenty of ways to add intensity: Hit the hills or add weights (try dumbbells or ankle weights) to really get that heart rate up. Intensity and energy cost of weighted walking vs. running for men and women. Miller JF, Stamford BA. Journal of applied physiology (Bethesda, Md. : 1985), 1987, Jul.;62(4):8750-7587.

5. Cycling

We've loved biking ever since we finally took off our training wheels. It just so happens to be a great way to fit in some exercise without putting a strain on your joints. And you don't even need to sign up for an indoor cycling class to see results. Try this 30-minute at-home cycling workout.

6. Rowing

Here's a super-easy way to get in some cardio while also pretending that you're soaking up some sun on a boat. Of course, the florescent lights in the gym eventually snap you back to reality. But at least you'll be working out your arms, back, legs, andcore. (Give this 30-minute rowing workout a go.) Score!

7. Kayaking

Want to actuallyhit the water? Grab a kayak and jump in (or maybe don't jump in, if you want to stay dry)! Kayaking works your arms and core (no crunches necessary), and you can see some stellar sights along the way.

11. Yoga

The ancient practice will have you feeling the burn without feeling the pain. So add some downward dogs and half moons to your fitness routine. Or try aerial yoga to really take your practice to new heights.

12. Pilates

You aren't going to get a strong core by doing crunches all day long. Try Pilates instead—plus, you'll seriously improve your flexibility without putting too much strain on your joints.

13. TRX

TRX gets its name because it lets users do total-body resistance exercises using a strap suspension system (say that three times fast). The workout is easy on your joints but challenging for the rest of your body. Once you learn the ropes, see if you can master these 45 TRX exercises.